Cardiac Magnetic Resonance Imaging of COVID-19-Associated Cardiac Sequelae: A Systematic Review.

Background: Many COVID-19 survivors experience persistent COVID-19 related cardiac abnormalities weeks to months after recovery from acute SARS-CoV-2 infection. Non-invasive cardiac magnetic resonance (CMR) imaging is an important tool of choice for clinical diagnosis of cardiac dysfunctions. In this systematic review, we analyzed the CMR findings and biomarkers of COVID-19 related cardiac sequela after SARS-CoV-2 infection. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), we conducted a systematic review of studies that assessed COVID-19 related cardiac abnormalities using cardiovascular magnetic resonance imaging. A total of 21 cross-sectional, case-control, and cohort studies were included in the analyses. Results: Ten studies reported CMR results < 3 months after SARS-CoV-2 infection and 11 studies > 3 months after SARS-CoV-2 infection. Abnormal T1, abnormal T2, elevated extracellular volume, late gadolinium enhancement and myocarditis was reported less frequently in the > 3-month studies. Eight studies reported an association between biomarkers and CMR findings. Elevated troponin was associated with CMR pathology in 5/6 studies, C-reactive protein in 3/5 studies, N-terminal pro-brain natriuretic peptide in 1/2 studies, and lactate dehydrogenase and D-dimer in a single study. The rate of myocarditis via CMR was 18% (154/868) across all studies. Most SARS-CoV-2 associated CMR abnormalities resolved over time. Conclusions: There were CMR abnormalities associated with SARS-CoV-2 infection and most abnormalities resolved over time. A panel of cardiac injury and inflammatory biomarkers could be useful in identifying patients who are likely to present with abnormal CMR pathology after COVID-19. Multiple mechanisms are likely responsible for COVID-19 induced cardiac abnormalities.

Targeted Deletion of Interleukin-6 in a Mouse Model of Chronic Inflammation Demonstrates Opposing Roles in Aging: Benefit and Harm.

Chronic inflammation (CI) in older adults is associated with reduced health span and life span. Interleukin-6 (IL-6) is one CI marker that is strongly associated with adverse health outcomes and mortality in aging. We have previously characterized a mouse model of frailty and chronic inflammatory pathway activation (IL-10tm/tm, IL-10 KO) that demonstrates the upregulation of numerous proinflammatory cytokines, including IL-6. We sought to identify a more specific role for IL-6 within the context of CI and aging and developed a mouse with targeted deletion of both IL-10 and IL-6 (IL-10tm/tm/IL-6tm/tm, DKO). Phenotypic characteristics, cytokine measurements, cardiac myocardial oxygen consumption, physical function, and survival were measured in DKO mice and compared to age- and gender-matched IL-10 KO and wild-type mice. Our findings demonstrate that selective knockdown of IL-6 in a frail mouse with CI resulted in the reversal of some of the CI-associated changes. We observed increased protective mitochondrial-associated lipid metabolites, decreased cardiac oxaloacetic acid, improved myocardial oxidative metabolism, and better short-term functional performance in DKO mice. However, the DKO mice also demonstrated higher mortality. This work shows the pleiotropic effects of IL-6 on aging and frailty.